I'm not so sure this is going to work out for you anyway. Suppose you pick sdd and sdf as your boot path devices. If a trespass occurs, then those may well become sdc and sde, and you won't be able to boot if you're nailed down to sdd and sdf. Assuming that SLES doesn't work with the by-id devices and that you're at relatively recent FLARE and dm-multipath code, you might want to consider ALUA mode if you absolutely have to boot from the array. However, I don't understand why by-id wouldn't work. My SLES 11 box's device.map contains (among others): (hd0) /dev/disk/by-id/scsi-SFUJITSU_MAJ3182MC_50085460 Which can be obtained from: # /lib/udev/scsi_id -g -u /dev/sda SFUJITSU_MAJ3182MC_50085460 Did you try using that identifier in your device.map file? Cheers, Jerry --------------------------------------------- eService at your fingertips: http://powerlink.emc.com -----Original Message----- From: dm-devel-bounces@xxxxxxxxxx [mailto:dm-devel-bounces@xxxxxxxxxx] On Behalf Of dm-devel-request@xxxxxxxxxx Sent: Saturday, February 20, 2010 12:00 PM To: dm-devel@xxxxxxxxxx Subject: dm-devel Digest, Vol 72, Issue 20 Send dm-devel mailing list submissions to dm-devel@xxxxxxxxxx To subscribe or unsubscribe via the World Wide Web, visit https://www.redhat.com/mailman/listinfo/dm-devel or, via email, send a message with subject or body 'help' to dm-devel-request@xxxxxxxxxx You can reach the person managing the list at dm-devel-owner@xxxxxxxxxx When replying, please edit your Subject line so it is more specific than "Re: Contents of dm-devel digest..." Today's Topics: 1. Re: multipath: Determine which device to use for grubdevice.map file (berthiaume_wayne@xxxxxxx) 2. Re: multipath: Determine which device to use for grubdevice.map file (David Huffman) 3. Re: multipath: Determine which device to use for grubdevice.map file (malahal@xxxxxxxxxx) ---------------------------------------------------------------------- Message: 1 Date: Fri, 19 Feb 2010 14:53:52 -0500 From: <berthiaume_wayne@xxxxxxx> To: <dm-devel@xxxxxxxxxx> Subject: Re: multipath: Determine which device to use for grubdevice.map file Message-ID: <8F08A56613D77044BD153E2AC5DA0F8403B0E9F0@xxxxxxxxxxxxxxxxxxxxxxxx> Content-Type: text/plain; charset="US-ASCII" Hi David. For SLES you should be using /dev/disk/by-id/36006016094511600449d92ae1937d611-part2 for a typical root partition. Regards, Wayne. -----Original Message----- From: dm-devel-bounces@xxxxxxxxxx [mailto:dm-devel-bounces@xxxxxxxxxx] On Behalf Of David Huffman Sent: Thursday, February 18, 2010 8:15 PM To: dm-devel@xxxxxxxxxx Subject: multipath: Determine which device to use for grubdevice.map file I need to configure a dm-multipath device (mpatha) as a boot disk in a script. For RHEL it appears I can put the mpath device in my device.map file. However, for SLES 11 if I use the mpath device, grub fails with "Floating point exception". For SLES I have to use the underlying path device (sd[a-z]). I know which devices make up my multipath disk. Here is an example that shows my problem. mpatha (36006016094511600449d92ae1937d611) dm-0 DGC,DISK [size=50G][features=1 queue_if_no_path][hwhandler=1 emc][rw] \_ round-robin 0 [prio=2][active] \_ 2:0:1:0 sdd 8:48 [active][ready] \_ 3:0:1:0 sdf 8:80 [active][ready] \_ round-robin 0 [prio=0][enabled] \_ 2:0:0:0 sdc 8:32 [active][ready] \_ 3:0:0:0 sde 8:64 [active][ready] Out of the 4 paths, only two (sdd and sdf) are active. This output is not very good to parse through in a script to determine which disks I can specify in my device.map file. Is there a command or better way to determine which underlying paths I can use in my device.map file. For clarification, here is a breakdown of my device.map entries and the results: (hd0) /dev/mapper/mpatha - FAIL with "Floating point exception" (hd0) /dev/sdc - FAIL with "Error 21: Selected disk does not exist" (hd0) /dev/sdd - Success!!! I would rather put the mpath device in device.map, but that does not appear to be an option for SLES. Is there a way to determine the underlying path device that is "active" and not just enabled? Right now I can run "dd if=/dev/sdc of=/dev/null bs=512 count=1 2>/dev/null; echo $?" This will tell me in the device can be written to. Any suggestions would be helpful. - David -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel ------------------------------ Message: 2 Date: Fri, 19 Feb 2010 14:32:52 -0800 From: David Huffman <dm-devel@xxxxxxxxxx> To: device-mapper development <dm-devel@xxxxxxxxxx> Subject: Re: multipath: Determine which device to use for grubdevice.map file Message-ID: <4B7F1194.2040201@xxxxxxxxxx> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Thanks for the response Wayne, but this does me no good. You cannot use the /dev/disk/by-id/* entries for device.map. You have to use the block device and not a link or dm-* device name. Essentially, I need to know which underlying paths can be written to directly. -David berthiaume_wayne@xxxxxxx wrote: > Hi David. > > For SLES you should be using > /dev/disk/by-id/36006016094511600449d92ae1937d611-part2 for a typical > root partition. > > Regards, > Wayne. > > -----Original Message----- > From: dm-devel-bounces@xxxxxxxxxx [mailto:dm-devel-bounces@xxxxxxxxxx] > On Behalf Of David Huffman > Sent: Thursday, February 18, 2010 8:15 PM > To: dm-devel@xxxxxxxxxx > Subject: multipath: Determine which device to use for > grubdevice.map file > > I need to configure a dm-multipath device (mpatha) as a boot disk in a > script. For RHEL it appears I can put the mpath device in my device.map > file. However, for SLES 11 if I use the mpath device, grub fails with > "Floating point exception". For SLES I have to use the underlying path > device (sd[a-z]). > > I know which devices make up my multipath disk. Here is an example that > shows my problem. > > mpatha (36006016094511600449d92ae1937d611) dm-0 DGC,DISK > [size=50G][features=1 queue_if_no_path][hwhandler=1 emc][rw] > \_ round-robin 0 [prio=2][active] > \_ 2:0:1:0 sdd 8:48 [active][ready] > \_ 3:0:1:0 sdf 8:80 [active][ready] > \_ round-robin 0 [prio=0][enabled] > \_ 2:0:0:0 sdc 8:32 [active][ready] > \_ 3:0:0:0 sde 8:64 [active][ready] > > Out of the 4 paths, only two (sdd and sdf) are active. This output is > not very good to parse through in a script to determine which disks I > can specify in my device.map file. Is there a command or better way to > determine which underlying paths I can use in my device.map file. > > For clarification, here is a breakdown of my device.map entries and the > results: > > (hd0) /dev/mapper/mpatha - FAIL with "Floating point exception" > > (hd0) /dev/sdc - FAIL with "Error 21: Selected disk does not exist" > > (hd0) /dev/sdd - Success!!! > > I would rather put the mpath device in device.map, but that does not > appear to be an option for SLES. Is there a way to determine the > underlying path device that is "active" and not just enabled? > > Right now I can run "dd if=/dev/sdc of=/dev/null bs=512 count=1 > 2>/dev/null; echo $?" > > This will tell me in the device can be written to. Any suggestions would > > be helpful. > > - David > > -- > dm-devel mailing list > dm-devel@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/dm-devel > > > -- > dm-devel mailing list > dm-devel@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/dm-devel > ------------------------------ Message: 3 Date: Fri, 19 Feb 2010 16:04:34 -0800 From: malahal@xxxxxxxxxx To: dm-devel@xxxxxxxxxx Subject: Re: multipath: Determine which device to use for grubdevice.map file Message-ID: <20100220000434.GA7527@xxxxxxxxxx> Content-Type: text/plain; charset=us-ascii > mpatha (36006016094511600449d92ae1937d611) dm-0 DGC,DISK > [size=50G][features=1 queue_if_no_path][hwhandler=1 emc][rw] > \_ round-robin 0 [prio=2][active] > \_ 2:0:1:0 sdd 8:48 [active][ready] > \_ 3:0:1:0 sdf 8:80 [active][ready] > \_ round-robin 0 [prio=0][enabled] > \_ 2:0:0:0 sdc 8:32 [active][ready] > \_ 3:0:0:0 sde 8:64 [active][ready] > > Out of the 4 paths, only two (sdd and sdf) are active. This output is > not very good to parse through in a script to determine which disks I > can specify in my device.map file. Is there a command or better way to > determine which underlying paths I can use in my device.map file. You can probably get it from "dmsetup status <device>", but it may be even harder to parse! Thanks, Malahal. ------------------------------ -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel End of dm-devel Digest, Vol 72, Issue 20 **************************************** -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
